About two and one-half billion years ago, life on Earth was still in its infancy. Complex organisms such as plants and animals had not yet appeared, but the planet was teeming with microscopic bacteria which thrived in the temperate and nutrient-rich environment. Greenhouse methane lingered in the atmosphere and trapped the sun's warmth, creating a climate very accommodating to the stew of microbes life that made their home on primitive Earth.
But a billion years of bacterial evolutionary progress was soon stunted by a catastrophic global event. Geologists find no signs of a great meteor impact nor a volcanic eruption, but they have uncovered the unmistakable geologic scars of rapid worldwide climate change. Average temperatures, which were previously comparable to our present climate, plummeted to minus 50 degrees Celsius and brought the planet into its first major ice age. This environmental shift triggered a massive die-off which threatened to extinguish all life on Earth, and paleoclimatologists have good reason to believe that this world-changing event was unwittingly caused by some of the planet's own humble residents: bacteria.”

"Just outside Butte, Montana lies a pit of greenish poison a mile and a half wide and over a third of a mile deep. It hasn't always been so - it was once a thriving copper mine appropriately dubbed “The Richest Hill in the World.” Over a billion tons of copper ore, silver, gold, and other metals were extracted from the rock of southwestern Montana, making the mining town of Butte one of the richest communities in the country, as well as feeding America’s industrial might for nearly a hundred years. By the middle of the twentieth century, the Anaconda Mining Company was in charge of virtually all the mining operations. When running underground mines became too costly in the 1950’s, Anaconda switched to the drastic but effective methods of “mountaintop removal” and open pit mining. Huge amounts of copper were needed to satisfy the growing demand for radios, televisions, telephones, automobiles, computers, and all the other equipment of America’s post-war boom. As more and more rock was excavated, groundwater began to seep into the pit, and pumps had to be installed to keep it from slowly flooding.

By 1983, the hill was so exhausted that the Anaconda Mining Company was no longer able to extract minerals in profitable amounts. They packed up all the equipment that they could move, shut down the water pumps, and moved on to more lucrative scraps of Earth. Without the pumps, rain and groundwater gradually began to collect in the pit, leaching out the metals and minerals in the surrounding rock. The water became as acidic as lemon juice, creating a toxic brew of heavy metal poisons including arsenic, lead, and zinc. No fish live there, and no plants line the shores. There aren’t even any insects buzzing about. The Berkeley Pit had become one of the deadliest places on earth, too toxic even for microorganisms. Or so it was thought."

"In the early 1990s, a Russian drilling rig encountered something peculiar two miles beneath the coldest and most desolate place on Earth. For decades, the workers at Vostok Research Station in Antarctica had been extracting core samples from deep scientific boreholes, and analyzing the lasagna-like layers of ice to study Earth's bygone climate. But after tunneling through 414,000 layers or so– about two miles into the icecap– the layers abruptly ended. The ice below that depth was relatively clear and featureless, a deviation the scientists were at a loss to explain. In search of answers, the men drilled on.

Unbeknownst to the Russians, their drill had mingled with the uppermost reaches of one of the largest freshwater lakes in the world; a pristine pocket of liquid whose ecosystem was separated from the rest of the Earth millions of years ago. As for what sort of organisms might lurk in that exotic environment today, no one can really be certain."